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HSQLDB example source code file (Like.java)
The HSQLDB Like.java source code/* * For work developed by the HSQL Development Group: * * Copyright (c) 2001-2010, The HSQL Development Group * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the HSQL Development Group nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG, * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * * * For work originally developed by the Hypersonic SQL Group: * * Copyright (c) 1995-2000, The Hypersonic SQL Group. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the Hypersonic SQL Group nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE HYPERSONIC SQL GROUP, * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * This software consists of voluntary contributions made by many individuals * on behalf of the Hypersonic SQL Group. */ package org.hsqldb; import org.hsqldb.lib.StringUtil; /** * Reusable object for processing LIKE queries. * * Enhanced in successive versions of HSQLDB. * * @author Thomas Mueller (Hypersonic SQL Group) * @version 1.8.0 * @since Hypersonic SQL */ // boucherb@users 20030930 - patch 1.7.2 - optimize into joins if possible // fredt@users 20031006 - patch 1.7.2 - reuse Like objects for all rows class Like { private char[] cLike; private int[] wildCardType; private int iLen; private boolean isIgnoreCase; private int iFirstWildCard; private boolean isNull; Character escapeChar; boolean hasCollation; boolean optimised; static final int UNDERSCORE_CHAR = 1; static final int PERCENT_CHAR = 2; Like(Character escape, boolean collation) { escapeChar = escape; hasCollation = collation; } /** * param setter * * @param s * @param ignorecase */ void setParams(Session session, String s, boolean ignorecase) { isIgnoreCase = ignorecase; normalize(session, s); optimised = true; } /** * Resets the search pattern; */ void resetPattern(Session session, String s) { normalize(session, s); } private String getStartsWith() { if (iLen == 0) { return ""; } StringBuffer s = new StringBuffer(); int i = 0; for (; (i < iLen) && (wildCardType[i] == 0); i++) { s.append(cLike[i]); } if (i == 0) { return null; } return s.toString(); } /** * Method declaration * * * @param o * * @return */ Boolean compare(Session session, String s) { if (s == null) { return null; } if (isIgnoreCase) { s = session.database.collation.toUpperCase(s); } return compareAt(s, 0, 0, s.length()) ? Boolean.TRUE : Boolean.FALSE; } /** * Method declaration * * * @param s * @param i * @param j * @param jLen * * @return */ private boolean compareAt(String s, int i, int j, int jLen) { for (; i < iLen; i++) { switch (wildCardType[i]) { case 0 : // general character if ((j >= jLen) || (cLike[i] != s.charAt(j++))) { return false; } break; case UNDERSCORE_CHAR : // underscore: do not test this character if (j++ >= jLen) { return false; } break; case PERCENT_CHAR : // percent: none or any character(s) if (++i >= iLen) { return true; } while (j < jLen) { if ((cLike[i] == s.charAt(j)) && compareAt(s, i, j, jLen)) { return true; } j++; } return false; } } if (j != jLen) { return false; } return true; } /** * Method declaration * * * @param pattern * @param b */ private void normalize(Session session, String pattern) { isNull = pattern == null; if (!isNull && isIgnoreCase) { pattern = session.database.collation.toUpperCase(pattern); } iLen = 0; iFirstWildCard = -1; int l = pattern == null ? 0 : pattern.length(); cLike = new char[l]; wildCardType = new int[l]; boolean bEscaping = false, bPercent = false; for (int i = 0; i < l; i++) { char c = pattern.charAt(i); if (bEscaping == false) { if (escapeChar != null && escapeChar.charValue() == c) { bEscaping = true; continue; } else if (c == '_') { wildCardType[iLen] = UNDERSCORE_CHAR; if (iFirstWildCard == -1) { iFirstWildCard = iLen; } } else if (c == '%') { if (bPercent) { continue; } bPercent = true; wildCardType[iLen] = PERCENT_CHAR; if (iFirstWildCard == -1) { iFirstWildCard = iLen; } } else { bPercent = false; } } else { bPercent = false; bEscaping = false; } cLike[iLen++] = c; } for (int i = 0; i < iLen - 1; i++) { if ((wildCardType[i] == PERCENT_CHAR) && (wildCardType[i + 1] == UNDERSCORE_CHAR)) { wildCardType[i] = UNDERSCORE_CHAR; wildCardType[i + 1] = PERCENT_CHAR; } } } boolean hasWildcards() { return iFirstWildCard != -1; } boolean isEquivalentToFalsePredicate() { return isNull; } boolean isEquivalentToEqualsPredicate() { return iFirstWildCard == -1; } boolean isEquivalentToNotNullPredicate() { if (isNull ||!hasWildcards()) { return false; } for (int i = 0; i < wildCardType.length; i++) { if (wildCardType[i] != PERCENT_CHAR) { return false; } } return true; } boolean isEquivalentToBetweenPredicate() { return iFirstWildCard > 0 && iFirstWildCard == wildCardType.length - 1 && cLike[iFirstWildCard] == '%'; } boolean isEquivalentToBetweenPredicateAugmentedWithLike() { return iFirstWildCard > 0 && cLike[iFirstWildCard] == '%'; } String getRangeLow() { return getStartsWith(); } String getRangeHigh() { String s = getStartsWith(); return s == null ? null : s.concat("\uffff"); } public String describe(Session session) { StringBuffer sb = new StringBuffer(); sb.append(super.toString()).append("[\n"); sb.append("escapeChar=").append(escapeChar).append('\n'); sb.append("isNull=").append(isNull).append('\n'); sb.append("optimised=").append(optimised).append('\n'); sb.append("isIgnoreCase=").append(isIgnoreCase).append('\n'); sb.append("iLen=").append(iLen).append('\n'); sb.append("iFirstWildCard=").append(iFirstWildCard).append('\n'); sb.append("cLike="); sb.append(StringUtil.arrayToString(cLike)); sb.append('\n'); sb.append("wildCardType="); sb.append(StringUtil.arrayToString(wildCardType)); sb.append(']'); return sb.toString(); } } Other HSQLDB examples (source code examples)Here is a short list of links related to this HSQLDB Like.java source code file: |
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